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Long J.-H.,Taiyuan University of Technology | Long J.-H.,Changan University | Guo W.-B.,Xishan Coal Electricity Group Co. | Li P.,Changan University | Li T.-L.,Changan University
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2010

Soils at different depths are sampled from 11 recent or apt-to-be landslides located in Jingyang County along the Jinghe River. Considering their geological environment and irrigation conditions, triaxial creep tests and direct shear creep tests on these undisturbed soil samples separately under different stress levels and moisture contents are performed to study their creep property. The findings are as follows: the creep deformation consists of 3 stages, namely, constant speed creep, acceleration creep and creep rupture, and the period from the acceleration creep to the creep rupture is significantly short; the rupture of the soil in sliding zone is characterized by plastic destruction; the corresponding strain capacity ε of the creep rupture is basically below 10%, and with the increase of the moisture content, ε of the creep rupture accordingly decreases; the results of destruction strain capacity by the direct shear creep tests under different moisture content conditions are all below 4%; and the stress-strain isochronic curves under time (t>0 min) are nearly a bunch of series of curves and exhibit a "normalization" phenomenon, demonstrating that the soil in this sliding zone has consistent creep characteristics. The intrinsic relationship between the creep property and the prediction model of slope failure is also discussed. Experimental studies and theoretical discussions are given for forecasting loess landslides.

Hu Q.,North China University of Water Conservancy and Electric Power | Cui X.,China University of Mining and Technology | Kang X.,Xishan Coal Electricity Group Co. | Lei B.,North China University of Water Conservancy and Electric Power | And 2 more authors.
Caikuang yu Anquan Gongcheng Xuebao/Journal of Mining and Safety Engineering | Year: 2014

Based on the analysis of the influence of the Knothe time function parameter, This paper puts forward that before the Knothe time function is convergent, for the same point in time, the smaller the value of becomes, the smaller the Knothe time function value becomes, and vice versa. The influence of the different parameter on the Knothe time function value is very significant, especially when t∈[0, 0.2]. According to the general laws of surface subsidence and the size at which the gob reached the full extraction, a new evaluation parameter model of Knothe time function (named the probability integral calculate the parameter method) was established. By comparing the measured value and the calculated value of the model of Pingan coal mine, Fuli coal mine and Suncun coal mine, the correctness of the model is verified. By applying the model to several observational subsidence data of the strike line of the 29401 face, and comparing the measured data and predictions, the practicality and reliability of the Knothe time function parameter calculation model is established in this paper.

Bui M.,China University of Mining and Technology | Bui M.,Hanoi University of Mining and Geology | Lu Y.,China University of Mining and Technology | Guo W.,China University of Mining and Technology | And 2 more authors.
Caikuang yu Anquan Gongcheng Xuebao/Journal of Mining and Safety Engineering | Year: 2014

In order to ensure the stability of the thick coal seam with parting in gob-side entry in longwall top coal caving, and to increase the safety and effectiveness in mining, the numerical model has been employed to analyse the stress distribution of gob-side entry, plastic strain area distribution and movement of rocks under the different conditions of dirt bands. Result of research shows that the existence of band layers has destroyed the continuity of the surrounding rock, which causes the roads becoming unstable; while in the thick layers, surrounding rocks are relatively stable. When hardness of the layers and that of coal seam are the same, and these bands lay on the top of road, the rocks surrounding the roads are also relatively stable. And on this basis, an appropriate technique of surrounding rock control is proposed, in which a combination of rock bolting-wire mesh and steel rectangular shape support are chosen and the suitable parameters are identified. Engineering practice has proved the rationality of the proposed technique, ensuring the safety and effectiveness in long wall extraction. ©, 2014, China University of Mining and Technology. All right reserved.

Dong R.B.,LIAONING Technical University | Li Z.S.,Xishan Coal Electricity Group Co. | Xu W.X.,LIAONING Technical University | Xie M.,LIAONING Technical University
Advanced Materials Research | Year: 2013

For the purpose of optimizing the dynamic characteristics of large forging equipment multilevel cartridge valves, according to the structure and principle of the Rexroth's LC series cartridge elements, using AMESim simulation software, the influence of forging equipment cartridge valves switching characteristics be discussed respectively from the damping R2, the damping R1, the load pressure. The results show that the damping R1, the damping R2, the system pressure, and the work load to cartridge valves switching characteristics have certain effect[2]. The research gives a method for analyzing and adjusting the cartridge valve response characteristics. © (2013) Trans Tech Publications, Switzerland.

Meng J.,China University of Mining and Technology | Meng J.,Xishan Coal Electricity Group Co. | Jiang Z.J.,China University of Mining and Technology | Zhang M.M.,China University of Mining and Technology | Qin Y.P.,China University of Mining and Technology
Advanced Materials Research | Year: 2013

Based on fluid mechanics, the theory of gas-solid flow and jet theory etc. Dust migration regularity in fully mechanized workface was studied and simulated under far-pressing-near-suction ventilation with FLUENT Simulation technology. When the ratio of blowing to suction(μ) is larger than 1, the range of high dust concentration reduces and the maximum dust concentration decreases. The sketch of flow field of the different μ, the short of traditional far-pressing-near-suction ventilation and the superiority in practical of dust removal mode with the forced ventilation shunt were summarized and analyzed. The dust migration regularity in different shunt parameters (K) in this mode was simulated. Increasing shunted air quantities (Q) is beneficial to the control of dust diffusion in the roadway. But dust concentration near pressure air side will increase if the value of the shunted air quantities is over a critical value. © (2013) Trans Tech Publications, Switzerland.

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